Water hammering in water pipes is caused by a combination of pressure and velocity. Namely, where a quick closing valve snaps shut, pressure and velocity result in hammering. To counteract this, in the prior art, known is the use of a water hammer arrester (e.g., U.S. Pat. No. 2,273,766 (Tower, 1942)).
A water hammer arrester is used in any place where a quick close valve exists in a plumbing system. While curing the problem in a residence can be as simple as installing water hammer arresters on both the cold supply line and the hot supply line, it is more common to find installations of these water hammer arresters at multiple places in the house, for instance: one located at the washing machine, one located at the dishwasher, etc.
A typical water hammer arrester comprises a cylinder including a piston having rubber o-rings that is able to move within the cylinder. The various components (other than the o-rings) of such a water hammer arrester are typically comprised of metal. The cylinder containing an air chamber that is pre-charged with a certain pressure of inert gas, inert gas being used so as to prevent corrosion of the metal components. As the water pressure within the line changes, the water hammer arrester absorbs the kinetic energy propagated in the water thereby preventing hammering. If this energy is not absorbed, the energy would oscillate in recurring cycles through the water between the valve and the source of the pressure until the energy is dissipated, causing the undesirable hammering sound/effect until dissipation takes place.